To elaborate a bit more: We assume you want page breaks in PDFs, generated from articles. Our current PDF generator runs in the browser and uses the library jsPDF, which interprets the HTML richtext content generated by TinyMCE.
Unfortunately, while officially supported, jsPDF does not respect page breaks when using HTML as input. At least we have not been able to get it work.
Regarding your other question: There is no way to add or enable plugins or features of TinyMCE that we have not integrated into the platform. Some features are disabled because they are too esoteric, others because they cause issues.
If you want specific features of TinyMCE, please list them and we can have a look at enabling them.